Effect of anti-CD52 antibody alemtuzumab on ex-vivo culture of umbilical cord blood stem cells.
BACKGROUND
Excessive maturation of hematopoietic cells leads to a reduction of long-term proliferative capability during cord blood (CB) expansion. In this study, we report the effects of anit-CD52 (Alemtuzumab, Campath) on both short- and long-term ex vivo expansion of CB hematopoietic stem cells (HSC) by evaluating the potential role of Alemtuzumab in preserving the repopulating capability in CB HSC and nonlymphoid progenitors.


METHODS
Ex vivo expansion experiments were carried out using freshly purified CB CD34(+)cells in StemSpantrade mark SFEM medium in the presence of stem cell factor, Flt3-Ligand and thrombopoietin at 50 ng/ml. Alemtuzumab (10 microg/ml) was used to deplete CD52(+) cells during the cultures. Flow cytometry was used to monitor CB HSC and their differentiation. Colony forming unit (CFU) assays and long term culture-initiating cell (LTC-IC) assays were performed on cells obtained from day 0 (before culture) and day 14 after cultures. Secondary cultures was performed using CD34(+) cells isolated at 35 days from primary cultures and further cultured in StemSpantrade mark SFEM medium for another 14 days to confirm the long term effect of alemtuzumab in liquid cultures.


RESULTS
Compared to cytokines alone, addition of alemtuzumab resulted in a significant increase in total nucleated cells, absolute CD34(+) cells, myeloid and megakaryocytic progenitors, multi-lineage and myeloid CFU and LTC-IC.


CONCLUSIONS
The results from current study suggested that the use of alemtuzumab for ex vivo expansion of CBHSC maybe advantageous. Our findings may improve current technologies for CBHSC expansion and increase the availability of CB units for transplantation. However, in vivo studies using animal models are likely needed in further studies to test the hematopoietic effects using such expanded CB products.
Lim
Che K
CK
Department of Hematology, Singapore General Hospital, Outram Road, Singapore. lim.che.kang@sgh.com.sg
Sun
Li
L
Feng
Qi
Q
Law
Ping
P
Chua
Wei T
WT
Lim
Shy N
SN
Hwang
William Y K
WY
D000074323:Alemtuzumab; D000911:Antibodies, Monoclonal / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology*; D018952:Antigens, CD34 / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D000074301:CD52 Antigen; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D002454:Cell Differentiation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology*; D006023:Glycoproteins / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D008533:Megakaryocytes / Q000166:cytology / Q000276:immunology; D022423:Myeloid Cells / Q000166:cytology / Q000276:immunology
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm; D015703:Antigens, CD; D018952:Antigens, CD34; D000951:Antigens, Neoplasm; D000074301:CD52 Antigen; D006023:Glycoproteins; D000074323:Alemtuzumab